1. Field of the Invention
The present invention relates to torque transmission devices and, more particularly, to a one-way, continuous drive tool cartridge and method of manufacturing.
2. Description of the Prior Art
The prior art is replete with one-way, or unidirectional, torque transmission devices such as socket wrenches and the like. Early mechanism designs affording relative rotation in a single direction generally incorporated "step-acting" ratchet wheel configurations. Later developments implemented "stepless-acting" embodiments wherein a central rotating body moved relative to an outside head. With such devices, the rotation of a central body is usually controlled either by the ratchet wheel or a one-way clutch arrangement. One such clutch arrangement of contemporary design includes a series of roller bearings housed within wedge-shaped cavities in the outside head. When rotation of the central body is attempted in a first direction, the bearings are permitted to move in the direction of an enlarged portion of the wedge-shaped openings, allowing rotation. When rotation is attempted in an opposite direction, the roller bearings are forced into narrower or constricted portions of the wedge cavities, thereby constraining rotation. Such universal, stepless-acting wrenches are common and one particular embodiment is shown in U.S. Pat. No. 3,590,667 to Berglein.
Subsequent prior art developments in unidirectional drive torque transmission systems have addressed refinements in the stepless-acting wrench. One particular area of improvement lies in the reduction of backlash in the drive actuation as well as the reduction of friction. Previously known ratchet wrenches had the disadvantage that they could only act in direct steps. This was a marked disadvantage for many conventional wrench applications. However, the wrench designs capable of stepless-acting actuation would often not facilitate the high torque forces necessary for certain loading configurations.
For the above reasons, great emphasis was placed upon the design of a one-way, torque clutch configuration for facilitating large rotational loads. One such torque-applying handtool is set forth as shown in U.S. Pat. No. 4,051,935 issued to Nakayama. The stepless mechanism of this patent comprises a polygonal shaft and series of rollers, each being placed in touch with each side of the polygon shaft. Each roller is selectively forced to one end or the other of each side so that the polygon shaft maybe turned in one direction when the tool handle is turned. Likewise, U.S. Pat. No. 3,534,836 issued to Dane illustrates a ratcheting mechanism comprising a number of paired sprag members pivotally mounted in spaced notches on a socket member rotatably mounted within a housing. One sprag of each pair will permit rotation of the housing relative to the socket member in the direction of the pivoted sprag, but will jam if the housing is rotated in the other direction. In this manner a ratcheting action is provided which is smoother and has no backlash in its 360.degree. rotation.
The aforesaid tool drive configurations are marked improvements over spring and pawl arrangements of early one-way drive systems. Such devices, as described above, utilized a spring biased pawl which generally engaged the teeth of a driven gear. The pawl was arranged so as to be cammed away from the gear teeth upon rotation of the gear in one direction but forced into engagement with the gear teeth to perform a wedging action that immobilized the gear when the gear was turned in the other direction. While effective in torque transmission, this type of ratchet necessarily included considerable drag between the pawl and gear as well as backward or opposite rotation known as backlash.
The technology of the above described patents have provided a numerous advantages for industry and the convenience of unidirectional torque drive systems have become widely accepted in various industries. For this reason, more recent developments have addressed further improved torque transmission tools. For example, co-pending patent application Ser. No. 479,843 filed 3/28/83 now abandoned sets forth and describes a unidirectional, stepless, clutch driven tool having numerous advantages over the prior art. As described therein, a torque transmitting drive shaft is provided with front and back socket drive elements on either side of a central shouldered portion. Means are provided for receiving the drive shaft within a central core to enable the drive shaft to be selectively, longitudinally positioned along the axis of rotation within the core to extend from a front or back face as needed. In this manner, when the drive shaft is longitudinally located to extend from a first face, a torque applied to the head is transmitted only in one direction by the drive shaft. When the drive shaft is longitudinally located in the opposite direction, extending from of the opposite face, a torque applied to the head, in an opposite direction is then transmitted only in that direction. This is accomplished with a single, one-way clutch.
It may thus be seen that improvements upon prior art clutch drive and bearing assemblies, unidirectional, stepless transmission systems and the like have focussed upon integral wrench assemblies including a driving head assembly and handle. The torque transmission tools described above each include such an assembly and, while effective in torque transmission, are limited by the availability of the wrench housing and handle assembly. In the event of damage to the clutch mechanism the wrench is generally of no further use.
It would be an advantage therefore, to provide a tool system having a unidirectional torque transmission device not integrally formed within the wrench housing. In this manner a damaged drive mechanism may be replaced in an economical fashion and assembly of the tool itself maybe facilitated by eliminating unnecessary assembly forces upon the generally delicate drive mechanism. The present invention provides such an improvement over the prior art by providing a unidirectional drive cartridge integrally housed within an assembly which may be mounted in a plurality of handle and wrench configurations. In this manner the cartridge may be utilized in a myriad of applications not heretofore possible. With a longitudinally positionable drive shaft extending from the cartridge the reliability and feasibility of non-integrated assemblies becomes a reality in accordance with the principles of the present invention.